Quad Driver, ECM question
Thread Starter
Racer
Joined: Mar 2007
Posts: 326
Likes: 0
From: McKinney Tx
Quad Driver, ECM question
I posted months and months ago trying to learn a little bit about my vehicle. Turns out (one of) my quad driver(s), is bad, my car is slow(but strong) and takes a lot of turns (10+) to start up, then with the rich smell out the rear.
I have been driving it for a while like this, but finally have the funds to fix it. I call local shops but nobody really sounds like they can give me a lowdown on what really has to happen to get my power back.
1993 lt1
Vortech Supercharger Kit
Power effects exhaust
Thats about it.
Anybody that really knows this stuff and could point me in the right direction I would really appreciate the help.
Also, The check engine light will only come on for a few seconds at a time then its gone for a couple days. My mechanic when doing the u joints said it was the quad driver code, thats all I really have to go on.
I apologize for being so ignorant to my own vehicle, I was a sport bike rider before this and took a few too many head landings I suppose, just trying to get this knowledge. Thanks all.
I have been driving it for a while like this, but finally have the funds to fix it. I call local shops but nobody really sounds like they can give me a lowdown on what really has to happen to get my power back.
1993 lt1
Vortech Supercharger Kit
Power effects exhaust
Thats about it.
Anybody that really knows this stuff and could point me in the right direction I would really appreciate the help.
Also, The check engine light will only come on for a few seconds at a time then its gone for a couple days. My mechanic when doing the u joints said it was the quad driver code, thats all I really have to go on.
I apologize for being so ignorant to my own vehicle, I was a sport bike rider before this and took a few too many head landings I suppose, just trying to get this knowledge. Thanks all.
Drifting
Joined: Sep 2005
Posts: 1,867
Likes: 3
From: Pasadena Maryland
The Quad Driver is an Integrated Circuit(Computer Chip) that is soldered into the ECM(Box above battery) The only thing I know of is to replace your ECM or send it out to have it fixed. Mid America Corvette will do it. The 92 and 93 are the only 2 years for that ECM, they are extremely hard to come by. Last I checked NONE in the GM parts system. Sometimes you see one on E-Bay.
If you know someone with a 92 or 93 maybe you cam install their ECM to be sure before you start spending money?
If you know someone with a 92 or 93 maybe you cam install their ECM to be sure before you start spending money?
Safety Car
Joined: Jun 2006
Posts: 3,629
Likes: 28
From: FL
kalister1 is correct that the quad driver relays are in the ECM, however the circuits they control are what is monitored for conditions that will set the code.
You need to get the exact code and then trouble shoot using the Factory Service Manual or you may replace the ECM for nothing.
The quad driver relays control torque converter lock up, cooling fans, canister purge, and air pump switching. None of them are highly likely to be causing a loss of power in my opinion.
Also look to see if there is a temp sending unit installed in the left head between cylinders 1 and 3. There is none from the factory in that location, however when I added a low temp cooling fan switch to my 93 rather than reprogram the ECM to turn the fans on sooner, that is where it is installed.
Since installing my low temp fan switch my ECM sets the code for quad driver #3 circuit because it sees the fan circuit grounded when it is not commanding fan operation, DTC 28. The ECM will not illuminate the check engine light for this code. If your car has a low temp fan switch in that location it may be doing the same, best of luck.
You need to get the exact code and then trouble shoot using the Factory Service Manual or you may replace the ECM for nothing.
The quad driver relays control torque converter lock up, cooling fans, canister purge, and air pump switching. None of them are highly likely to be causing a loss of power in my opinion.
Also look to see if there is a temp sending unit installed in the left head between cylinders 1 and 3. There is none from the factory in that location, however when I added a low temp cooling fan switch to my 93 rather than reprogram the ECM to turn the fans on sooner, that is where it is installed.
Since installing my low temp fan switch my ECM sets the code for quad driver #3 circuit because it sees the fan circuit grounded when it is not commanding fan operation, DTC 28. The ECM will not illuminate the check engine light for this code. If your car has a low temp fan switch in that location it may be doing the same, best of luck.
Drifting
Joined: Sep 2005
Posts: 1,867
Likes: 3
From: Pasadena Maryland
kalister1 is correct that the quad driver relays are in the ECM, however the circuits they control are what is monitored for conditions that will set the code.
You need to get the exact code and then trouble shoot using the Factory Service Manual or you may replace the ECM for nothing.
The quad driver relays control torque converter lock up, cooling fans, canister purge, and air pump switching. None of them are highly likely to be causing a loss of power in my opinion.
Also look to see if there is a temp sending unit installed in the left head between cylinders 1 and 3. There is none from the factory in that location, however when I added a low temp cooling fan switch to my 93 rather than reprogram the ECM to turn the fans on sooner, that is where it is installed.
Since installing my low temp fan switch my ECM sets the code for quad driver #3 circuit because it sees the fan circuit grounded when it is not commanding fan operation, DTC 28. The ECM will not illuminate the check engine light for this code. If your car has a low temp fan switch in that location it may be doing the same, best of luck.
You need to get the exact code and then trouble shoot using the Factory Service Manual or you may replace the ECM for nothing.
The quad driver relays control torque converter lock up, cooling fans, canister purge, and air pump switching. None of them are highly likely to be causing a loss of power in my opinion.
Also look to see if there is a temp sending unit installed in the left head between cylinders 1 and 3. There is none from the factory in that location, however when I added a low temp cooling fan switch to my 93 rather than reprogram the ECM to turn the fans on sooner, that is where it is installed.
Since installing my low temp fan switch my ECM sets the code for quad driver #3 circuit because it sees the fan circuit grounded when it is not commanding fan operation, DTC 28. The ECM will not illuminate the check engine light for this code. If your car has a low temp fan switch in that location it may be doing the same, best of luck.
Melting Slicks
Joined: Feb 2005
Posts: 2,135
Likes: 0
From: Sebastian Florida
St. Jude Donor '06
When one of my fan relays went bad, it set a DTC 28 and my check engine light did come on. I have had both a DTC 26 and 28, 26 was a bad wire going to the EGR and both set the check engine light on.
Only if you leave the code unfixed for a while will it cause the ECM to go bad(ask me how I know), pull the codes and get back with results. Each quad driver monitors several sensors, so just because you get a quad driver code, do not assume it is just one sensor.
Only if you leave the code unfixed for a while will it cause the ECM to go bad(ask me how I know), pull the codes and get back with results. Each quad driver monitors several sensors, so just because you get a quad driver code, do not assume it is just one sensor.
Thread Starter
Racer
Joined: Mar 2007
Posts: 326
Likes: 0
From: McKinney Tx
My mechanic (is real short when he talks to you) said there were bad sensors but he replaced them, something about they may have messed up the quad driver in the first place.
Also, with all the fan talk, this doesnt seem like anything that should be making me have to turn her over 20 times to start and have a rich smell.
Also, with all the fan talk, this doesnt seem like anything that should be making me have to turn her over 20 times to start and have a rich smell.
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Melting Slicks
Joined: Feb 2005
Posts: 2,135
Likes: 0
From: Sebastian Florida
St. Jude Donor '06
No, should not effect starting. I am having the same problem now and I have narrowed it down to injector(s) bad or bad injector(s) connector. Still have to check the connectors.
Thread Starter
Racer
Joined: Mar 2007
Posts: 326
Likes: 0
From: McKinney Tx
I dont know enough about these vehicles to get this figured out. So if my quad driver is indeed messed up, then I have to replace the ecm, but even that wont account for the lack in performance?
Le Mans Master
Joined: Dec 2004
Posts: 5,789
Likes: 8
From: Myrtle Beach SC
St. Jude Donor '05-'06
You need to add some info. Starting issue is the same both hot and cold? Smells like flooding to me cannister purge could be plugged up check the hoses to and from it.
Melting Slicks
Joined: Feb 2005
Posts: 2,135
Likes: 0
From: Sebastian Florida
St. Jude Donor '06
Quad error means that one of the quad drivers is reading a signal from a sensor out of normal range or is not get a signal from a sensor. After a long period of time, this can cause the driver to go bad and then you need to replace the ECM.
Safety Car
Joined: Jun 2006
Posts: 3,629
Likes: 28
From: FL
When one of my fan relays went bad, it set a DTC 28 and my check engine light did come on. I have had both a DTC 26 and 28, 26 was a bad wire going to the EGR and both set the check engine light on.
Only if you leave the code unfixed for a while will it cause the ECM to go bad(ask me how I know), pull the codes and get back with results. Each quad driver monitors several sensors, so just because you get a quad driver code, do not assume it is just one sensor.
Only if you leave the code unfixed for a while will it cause the ECM to go bad(ask me how I know), pull the codes and get back with results. Each quad driver monitors several sensors, so just because you get a quad driver code, do not assume it is just one sensor.
Page 6E3-A-56 which details diagnosis of DTC 26 does not make the same statement so it may well illuminate the light, I have no experience with that DTC.
No question that problems in the quad driver circuits can cause the ECM to fail if not corrected, but that depends on the problem, another good reason to diagnose using the service manual rather than trying parts.
I would not risk a new or borrowed ECM without first running the appropriate test procedure for the code in question.
Melting Slicks
Joined: Feb 2005
Posts: 2,135
Likes: 0
From: Sebastian Florida
St. Jude Donor '06
According to the service manual page 6E3-A-60, DTC 28 will not turn on the check engine light, and that has been my experience since the code is set immediately when my low temp fan switch grounds the relay.
Page 6E3-A-56 which details diagnosis of DTC 26 does not make the same statement so it may well illuminate the light, I have no experience with that DTC.
No question that problems in the quad driver circuits can cause the ECM to fail if not corrected, but that depends on the problem, another good reason to diagnose using the service manual rather than trying parts.
I would not risk a new or borrowed ECM without first running the appropriate test procedure for the code in question.
Page 6E3-A-56 which details diagnosis of DTC 26 does not make the same statement so it may well illuminate the light, I have no experience with that DTC.
No question that problems in the quad driver circuits can cause the ECM to fail if not corrected, but that depends on the problem, another good reason to diagnose using the service manual rather than trying parts.
I would not risk a new or borrowed ECM without first running the appropriate test procedure for the code in question.
Test the fan relays by jumping the A and B terminal and turning the ignition key to the ON position, do not start.
If the fans come on, then the ECM is fine and you have bad fan relays or another sensor is bad. Remember that quad drivers controllers control multiple sensors.
Thread Starter
Racer
Joined: Mar 2007
Posts: 326
Likes: 0
From: McKinney Tx
No, a quad driver error does not mean you have to replace the ECM. You will if the problem is left unchecked for a long period of time.
Quad error means that one of the quad drivers is reading a signal from a sensor out of normal range or is not get a signal from a sensor. After a long period of time, this can cause the driver to go bad and then you need to replace the ECM.
Quad error means that one of the quad drivers is reading a signal from a sensor out of normal range or is not get a signal from a sensor. After a long period of time, this can cause the driver to go bad and then you need to replace the ECM.
Le Mans Master
Joined: Dec 2004
Posts: 5,789
Likes: 8
From: Myrtle Beach SC
St. Jude Donor '05-'06
You guys can argue about the quad driver all day long but it may just be shooting the messenger. If that driver has anything to do with the purge cannister it being bad will cause his symptoms. It might be filled with gas. I have seen it before they fail.
Thread Starter
Racer
Joined: Mar 2007
Posts: 326
Likes: 0
From: McKinney Tx
What steps do I take to check this? I would really like my 420+ ponies back. Im barely beating mustang gt's right now.
Le Mans Master
Joined: Dec 2004
Posts: 5,789
Likes: 8
From: Myrtle Beach SC
St. Jude Donor '05-'06
What code are you showing on the quad driver first? If it is 26 then it may be a cannister problem.Answer my previous question second.
26
Check EGR, Canister Purge and AIR pump relays with a digital Ohm meter. A resistance of less than 18 ohms indicates a bad relay. If OK, potential ECM failure.
26
Check EGR, Canister Purge and AIR pump relays with a digital Ohm meter. A resistance of less than 18 ohms indicates a bad relay. If OK, potential ECM failure.
Le Mans Master
Joined: Dec 2004
Posts: 5,789
Likes: 8
From: Myrtle Beach SC
St. Jude Donor '05-'06
Here are the other Quad faults
27
Potential ECM or on a manual transmission car, potential upshift relay problem. Check relay, replace if less than 18 Ohms using a digital Ohm Meter.
28
Air conditioning Clutch relay and/or cooling fan relays. Check with digital Ohm meter, replace if less than 18 Ohms. If relays OK, potential ECM failure.
27
Potential ECM or on a manual transmission car, potential upshift relay problem. Check relay, replace if less than 18 Ohms using a digital Ohm Meter.
28
Air conditioning Clutch relay and/or cooling fan relays. Check with digital Ohm meter, replace if less than 18 Ohms. If relays OK, potential ECM failure.